1. Field of the Invention
The present invention relates to water flow measuring devices, and more particularly, to water flow measuring devices for use with fire-fighting equipment such as fire hydrants or firetruck pumps, where air is infused into the stream of water to disperse the stream to prevent damage to the surrounding environment due to the force of the water.
Water flow measuring and dispersing devices for measuring and dispersing the water flow of a fire hydrant are well known in the art. These devices generally include a pyramidal-shaped body provided with a measuring device such as a pitot tube or a manometer positioned in the water stream. Screens are provided to break up or cavitize the water stream to diffuse the stream over a greater area. The known devices generally spray the water without redirecting the stream.
2. Discussion of the Prior Art
In the prior art, various flow measuring devices and several dispersion or diffusion devices are disclosed. The particular types of flow measuring devices are, of course, conventional and are not of importance to this invention. The diffusion and measuring devices in the prior art, however, are subject to several disadvantages, which in most instances, lead to inaccurate measurements, which in turn may result in the diminished effectiveness of the hydrant or pumper truck which is subjected to the measurement procedure.
De Weese, et al., U.S. Pat. No. 4,047,668, discloses a water flow diffuser for use on a fire hydrant which incorporates a series of diffuser elements into a conical housing. The diffuser elements consist of a plurality of screens bolted or welded to the interior of the housing. The smaller end of the cone is opened towards the hydrant and is connected to the hydrant by a coupling section which is open to the atmosphere. The coupling section may be fitted with a measuring apparatus for measuring the flow rate of the water. Crossbars are also provided at the smaller end of the cone so that large objects, such as rocks, in the stream of water do not damage the screens, which diffuse and cavitate the water.
De Weese, et al. suffers from a typical but important disadvantage which results in inaccurate flow measurements. De Weese, et al. positions a measurement device in the coupling section, which is also conically shaped, and results in flow measurements being made at a point where the water stream has already expanded. The measurement is therefore inaccurate, and the pressure in the hydrant system cannot be properly and accurately determined. De Weese, et al. also suffers from the disadvantage that diffusion or dispersion of the water is caused by the screens, which serve to break up the stream. The result is that backpressure, especially if the conical housing of De Weese, et al. was to be completely enclosed, would also lead to inaccurate flow measurement.
Anderton, et al., U.S. Pat. No. 4,343,435, also discloses a fire hydrant diffuser device which has a flared rectangular or pyramidal shape and is provided with a pair of diffuser elements in stepped configuration which extend inwardly from the discharge end to meet at the center of the water stream. The overall cross-section of the diffuser elements forms a "V" shape. Anderton, et al., like De Weese, et al., also cavitates and disperses the water by breaking it up.
While Anderton, et al. does not disclose a measuring device for measuring the flow of water through the device, it is apparent that if one were provided, Anderton, et al. would suffer the same disadvantages as De Weese, et al. Anderton, et al.'s device has an expanding cross-section from the neck coupling at the hydrant, and accordingly a flow measuring device would have to be located in this area, resulting in inaccurate measurements. In addition, backpressure would also be a problem, since the diffuser elements restrict the flow of water by causing the stream to break up or cavitate.
Darley, U.S. Pat. No. 1,276,732, discloses a flow measurement device for fire hydrants which extends into the discharge orifice of a fire hydrant. The clamping arm attempts to measure the flow of the stream center. Darley does not disperse or direct the stream, nor is there any provision for the infusion of air into the stream itself.
The novel water flow measuring and dispersing device of the present invention obviates the disadvantages of the prior art and provides a highly accurate flow measurement device for fire fighting equipment such as hydrants or pumper trucks, which disperses the water stream to prevent damage to the surrounding environment. The dispersion of the water is accomplished by infusing air into the stream to diffuse the water, while at the same time avoiding the problem of backpressure which would lead to inaccurate flow measurements.